Multi-Sensor Temperature Control for Substrate Liquid Processing
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Solution Overview
Problem
Current substrate liquid processing systems for semiconductor wafers face challenges in achieving accurate temperature control of phosphoric acid aqueous solutions during wet-etching, leading to inconsistencies in etching rates due to reliance on single temperature sensors, which fail to account for temperature distributions within the processing tub.
Innovation Solution
The implementation of a substrate liquid processing apparatus with at least two temperature sensors positioned within the circulation system, including the processing tub and circulation line, allows for precise control of the heater's heat generation based on detection temperatures from these sensors, ensuring more accurate temperature management of the processing liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single temperature sensor is used to control the heater, then the device complexity is reduced, but the temperature control accuracy deteriorates due to temperature distribution variations within the processing tub
Solution Approach 1:
The processing tub is divided into multiple monitoring zones by placing temperature sensors at different positions (e.g., center and edge). Each sensor monitors the temperature in its specific zone, allowing the control system to account for spatial temperature variations and adjust heating accordingly, thereby improving overall temperature control accuracy without significantly increasing system complexity
Solution Approach 2:
Different regions of the processing tub are monitored with dedicated temperature sensors to capture local temperature characteristics. The control system uses this localized temperature information to provide differentiated heating control, ensuring that each region achieves and maintains the desired temperature uniformity
2Device complexity
If a single temperature sensor is used, then the control system is simpler, but the etching rate uniformity deteriorates due to inaccurate temperature management
Solution Approach 1:
The processing tub is divided into multiple monitoring zones by placing temperature sensors at different positions (e.g., center and edge). Each sensor monitors the temperature in its specific zone, allowing the control system to account for spatial temperature variations and adjust heating accordingly, thereby improving overall temperature control accuracy
Solution Approach 2:
Multiple temperature sensors provide continuous feedback on temperature distribution throughout the processing tub. The control system processes this feedback information and dynamically adjusts the heater output to maintain uniform temperature, ensuring consistent etching rates across all substrates
3Measurement precision
If multiple temperature sensors are deployed, then the temperature control accuracy improves, but the device complexity increases
Solution Approach 1:
The processing tub is divided into a limited number of strategic monitoring zones (e.g., 2-4 sensors at key positions like center and edge) rather than continuous monitoring. This segmentation approach captures the essential temperature distribution characteristics while keeping the sensor count and system complexity manageable
Solution Approach 2:
The system optimizes the number and positioning of temperature sensors to achieve the minimum necessary for accurate temperature control. By carefully selecting sensor locations and quantities, the system achieves high measurement precision while minimizing the increase in device complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This multi-sensor approach enables stable and accurate temperature control, reducing control delays and maintaining uniformity of the etching process, thereby improving the consistency and effectiveness of the wet-etching process for semiconductor wafers.
Implementation Method 1
a heater provided at the circulation line and configured to heat the processing liquid
Implementation Method 2
a pump provided at the circulation line and configured to generate a flow of the processing liquid flowing out from the processing tub and returning back to the processing tub
Data Source
AI summary
A substrate liquid processing apparatus includes a processing tub 34 which is configured to store therein a processing liquid and in which a processing of a substrate is performed by immersing the substrate in the stored processing liquid; a circulation line 50 connected to the processing tub; a pump 51 provided at the circulation line and configured to generate a flow of the processing liquid flowing out from the processing tub and returning back to the processing tub after passing through the circulation line; and a heater 52 provided at the circulation line and configured to heat the processing liquid. At least two temperature sensors 81 to 83 are provided at different positions within a circulation system including the processing tub and the circulation line. Controllers 90 and 100 control a heat generation amount of the heater based on detection temperatures of the at least two temperature sensors.